Track 3 · Booking and Search
Design BookMyShow / IRCTC (Seat Reservation)
One seat, two hopeful people, a payment in the middle and a clock running. How to sell every seat exactly once when a lakh of people hit Buy at 10:00 AM, and what to do when the money arrives after the hold has gone.
Interview problem30 min read
On this page
- Problem framing
- Questions I ask before drawing anything
- Requirements
- Estimation
- API
- Data model
- Building it up
- The catalog stays out of the booking path
- The seat map: reads that scale
- Not selling a seat twice
- The hold window
- Payment, and the webhook that arrives late
- The drop: waiting room, bots and fairness
- When something breaks halfway
- Bottlenecks, security, and what to watch
- Questions an interviewer will ask
- Interview Leveling Rubric